1. Field of the Invention;
The present invention relates to a method of producing an opening cylinder for an open-end spinning machine, comprising the step of applying to the surface of a body of the opening cylinder a spirally extending sawtooth wire
2. Description of the Prior Art;
For producing opening cylinders, a sawtooth wire is normally forced into threadlike grooves turned into the circumference of the body of the opening cylinder. This is described e.g. in DE-A-2 752 591. By means of opening cylinders produced in this way, the fibres of the fibre entanglement are separated into individual fibres and transported to the fibre guide channel of the open-end spinning machine. The opening cylinders are normally driven at a speed of 5000 to 12000 revolutions per minute. The speed depends on the material to be processed.
The hitherto known production methods prove to be time-consuming and expensive, since the grooves must first be turned into the circumference of the opening cylinder and the sawtooth wire must then be forced into said grooves.
Hence, it is the object of the present invention to improve a method for producing opening cylinders for an open-end spinning machine in such a way that the opening cylinder can be produced at a more reasonable price and with less expenditure of time.
According to the present invention, this object is achieved by the feature that the sawtooth wire is supplied continuously to the body and welded to said body.
This solution is simple and advantageous insofar as a pre-treatment of the surface of the opening cylinder is not necessary. The sawtooth wire is wound onto the body in a continuous process and is reliably and simply anchored to the opening cylinder by welding.
In this connection, it can be advantageous when the sawtooth wire is is supplied to the rotating body. This will simplify the production process still further. The equipment required for carrying out the method can be realized more easily than in the case of methods where the body is stationary and the sawtooth wire has to be conducted around said body.
According to an advantageous further development of the present invention, the body can be formed by winding a basic wire onto a rotating expansion arbor, whereby also the body can be produced rapidly and easily.
In this connection, it can be advantageous when the spirals which are formed by winding on the basic wire and which abut on one another are welded together during the winding operation. The same production method which is used for applying the sawtooth wire can then also be used for producing the body of the opening cylinder.
In this respect, it may in particular prove to be advantageous when the basic wire and the sawtooth wire are supplied simultaneously. It is then possible to produce the body and to apply the sawtooth wire to said body in one operation. On the basis of this improvement, the production method for a opening cylinder can be simplified substantially.
In this connection, it can be advantageous when the spirals formed by winding on the sawtooth wire are welded to the basic wire. The sawtooth wire can be anchored reliably on the opening cylinder in this way. p It may also prove to be advantageous when the spirals formed by winding on the sawtooth wire abut on one another and are welded together. The strength of finished opening cylinder can be increased still further in this way. The sawtooth wire can be connected to the body by welding and the spirals of the sawtooth wire can be connected to one another by welding in immediately successive production processes.
In order to simplify the production method still further, the welding can be carried out immediately when the basic wire or the sawtooth wire are being supplied. This will save additional time.
In this connection, it can also be advantageous when the welding is carried out continuously. Continuous welds can be produced in this way. On the one hand, the strength of the welds and, consequently, of the opening cylinder as a whole can be improved in this way and, on the other hand, continuous operating procedures, which can be carried out more rapidly, are possible.
In accordance with an alternative embodiment, the welding can also be carried out in the form of discontinuous welding processes, preferably a high-frequency pulsed current arc welding process or a spot welding process.. The manufacturing speed of the opening cylinder can be increased in this way.
In accordance with an advantageous further development of the method, at least one pressure roller can be provided by means of which the supplied sawtooth wire and/or basic wire is/are pressed against the body which has already been formed and/or against the sawtooth wire which has already been applied. This pressure roller guarantees that the spirals of the sawtooth wire and of the basic wire, respectively, abut on one another and that reliable welding can therefore be carried out as desired.
In this connection, it may be advantageous when the axis of rotation of the pressure roller extends at right angles to the axis of rotation of the body and of the expansion arbor, respectively. When the axis extends in this direction, a particularly high pressure can be applied parallel to the surface of the body and to the axis of rotation of the expansion arbor and of the body, respectively.
According to one embodiment of the method, the basic wire can form a body having an essentially smooth surface onto which the sawtooth wire is applied. This will simplify the production of the opening cylinder substantially. Due to the simple geometries, the production costs can be reduced as well.
In the case of one embodiment of the present method comprising the step of applying the sawtooth wire to a prefabricated body, it may prove to be advantageous when the body is essentially cylindrical. Due to the simple geometries, the method can be carried out at a particularly reasonable price.
In order to increase the strength of the sawtooth wire on the body, the body formed by the basic wire can be provided with spiral grooves which accommodate a base section of the sawtooth wire. In addition to the welded joint between the sawtooth wire and the body, a positive engagement between the sawtooth wire and the basic wire can then be realized as well.
In accordance with an advantageous further development of the present method, the finished body with the sawtooth wire can be given its final shape by turning. Very exacting tolerances of the finished opening cylinder can be realized in this way.
Since thermal stresses may occur due to the welding operation, it may prove to be advantageous when the body having the sawtooth wire welded thereon is straightened. Also this permits a realization of very exacting tolerances of the finished opening cylinder.
It may also prove to be advantageous when the welding method used is a precision welding method, preferably laser-beam welding or electron-beam welding.
It can also be of advantage when the basic wire consists of low-carbon steel. A particularly tenacious opening cylinder can be produced in this way.
In addition, it may of advantage when the the sawtooth wire consists of high-carbon steel. This steel is very suitable for heat treatment processes.
In addition or alternatively, the sawtooth wire may also consist of alloy steel or microalloy steel so as to achieve a particularly high strength.
It may also prove to be advantageous when the length of the cylinder body produced corresponds to the length of one or of a plurality of finished opening cylinders. When the cylinder body produced corresponds to the length of an opening cylinder, said opening cylinder can be produced in one operation. When it corresponds to the length of a plurality of opening cylinders, a plurality of opening cylinders can be produced in one operation, the opening cylinder being sub-divided into pieces of suitable length by cutting off.
According to the present invention, an opening cylinder is additionally provided, which comprises a body on the surface of which a spirally extending sawtooth wire is arranged. For solving the task according to the present invention and for achieving the advantages according to the present invention, such an opening cylinder is so conceived that the sawtooth wire is welded to said body.
It may, however, advantageous to form the body of the opening cylinder by at least one spirally wound basic wire.
In this connection, it may prove advantageous when, in the longitudinal direction of the body, the sawtooth wire borders on two neighbouring spirals of the body defined by the basic wire. At least two spirals of the basic wire can then be connected to one another by welding the spirals to the basic wire.
In this connection, it may prove to be advantageous when the spirals of the basic wire connected by the sawtooth wire are neighbouring spirals. The juxtaposed spirals of the basic wire can then always be interconnected via the sawtooth wire. The strength of the opening cylinder can be increased in this way.
In this respect it may be of advantage when the spirals of the body are only indirectly connected to one another due to the fact that they are welded to the spirals of the sawtooth wire. Hence, one operation will suffice to form the body and to weld it to the sawtooth wire.
For increasing the strength, the neighbouring spirals of the sawtooth wire can be welded together.
The strength of the opening cylinder can additionally be increased when two neighbouring spirals of the sawtooth wire are connected to one another as well as to the body due to through-welding. One welding operation will then suffice to realize a firm connection between two neighbouring spirals of the sawtooth wire and of the basic wire bordering thereon.